Dog deterrent

She said: "We ran a specific operation, working closely with festival organisers and stewards, using the passive drugs dogs... which was extremely successful. Often just the sight of these dogs is enough to make people hand their drugs over."

However, police are still appealing for help in solving the most serious crime of the weekend, when a 39-year-old man was attacked after leaving the festival with his young family.

The man is in a critical condition in London's St George's Hospital after suffering head injuries when he was punched and head-butted in King's Road, Guildford on Friday.

Det Sgt Anna Leahy said: "It's been five days since the victim was assaulted and he remains in a critical condition with life-threatening injuries.